1. Field of the Invention
The present invention relates to an image forming apparatus, and in particular relates to technology of determining whether the pressing state of an intermediate transfer belt and a mechanism which performs the transfer of toner images to and from the intermediate transfer belt is normal.
2. Description of the Related Art
Conventionally known is an image forming apparatus of a system which temporarily transfers a toner image formed with a development unit including a photoreceptor drum to an intermediate transfer belt, and further transfers the toner image on the circumferential surface of the intermediate transfer belt onto recording paper based on a secondary transfer roller. This kind of image forming apparatus includes, for example, a movement mechanism for causing a photoreceptor drum, which forms a part of the development unit to rotate in a direction of pressing against and separating from a circumferential surface of an intermediate transfer belt, a pressing/separation motor for applying rotational driving force to the movement mechanism, a drive control part for controlling the drive of the pressing/separation motor, and a pressing state sensor for detecting a state of the photoreceptor drum pressing the circumferential surface of the intermediate transfer belt. The drive control part drives the pressing/separation motor and causes the movement mechanism to transfer the intermediate transfer belt toward the photoreceptor drum so that only the black development unit presses the intermediate transfer belt during black-and-white image formation, and all development units of the respective colors presses the intermediate transfer belt during color image formation, and, at the point in time that the pressing state sensor detects a state where the circumferential surface of the intermediate transfer belt is being pressed by the photoreceptor drum, the drive control part stops the pressing/separation motor, and image formation is performed to the recording paper in this pressing state.